1. Field of the Invention
The present invention relates to a method of numerically and objectively measuring the soiling of floor surfaces and wall surfaces (hereinafter referred to as "floor surfaces or the like") of office buildings, hotels, large stores, hospitals, ships, airplanes, etc., in particular, the soiling of fiber floors such as carpets, and a floor surface cleaning control method and a floor surface cleaning evaluation method by using the measurement method.
2. Prior Art
The cleaning of office buildings, hotels, hospitals and other large buildings is often entrusted to cleaning service companies because of lack of time or other reasons. The purpose of cleaning is to maintain sanitary environments and good appearances by removing soil. Regarding the maintenance of sanitary environments, control standards have been specified by the so-called "Building Control Rule" (a rule for ensuring sanitary environments in buildings) and it can be said that standards to be observed for the present are available. However, regarding the maintenance of visual appearances, in particular, the removal of soil, standards to be used for an objective guide and measurement methods have not yet been established at all. For this reason, regarding the removal of soil at the time of the inspection and control of cleaning, so-called input control is used inevitably in actual situations, wherein inspection and control are performed by attaching importance to cleaning manuals, that is, depending on whether cleaning processes, time elapsed, etc. are proper or not, rather than the degree of soiling.
Contrary to the above description, an attempt has been made recently to measure the light reflectivity of surfaces to be cleaned, such as floor surfaces or the like (the surfaces are those to be cleaned, such as floor surfaces, wall surfaces and ceiling surfaces, including not only smooth flat surfaces but also unsmooth surfaces represented by fiber floor surfaces. In the disclosure described hereinafter, such surfaces are abbreviated to "floor surfaces or the like." When the term "surface" is used in relation to measurement methods, the term "measurement surface" is used.) in order to numerically and objectively grasp the soiling of surfaces. However, the light reflectivity changes significantly depending on not only the soiling conditions of the floor surfaces or the like but also other surface conditions of the floor surfaces or the like, in particular, the roughness of the surfaces. In particular, in the case of a fiber floor, such as a carpet, the reflection characteristic thereof is complicated and the color thereof appears in different shades of color depending on the viewing direction. For this reason, even if the light reflectivity of such a floor surface is decreased by soil, the light reflectivity may increase if the surface roughness is decreased by wear for example. The soiling is therefore not necessarily related to the change with time in light reflectivity. In addition, the light reflectivity cannot indicate any change in hue caused by soil, an important factor for maintaining good appearances. Because of these reasons, it is inappropriate and difficult to measure and grasp the soiling of the floor surfaces or the like by using light reflectivity, in particular, when unsmooth fiber floors, such as carpets, are used.